Crossing signal



July 19, 193-8. M. DQWILSON #2,124,480

vCROSSING SIGNAL I Fild March 18. 1955 v 3 SheefS-Sheet l July 19, 193s. M D, WILSQN 2,124,480

CROSS ING S IGNAL July 19, 1938. M. D. wlLsoN 1 2,124,480

` CROSSING SIGNAL Filed March 18, 1935 5 'Sheets-Sheet 5 Inwfrzfpr erqer. Milian.

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Patented July 19, 1938 UNITED STATES PATENTr orrles Application March 18,

13 Claims.

This invention relates to traino control devices, particularly to automatic signal mechanisms for railroad crossings, and is directed to an improvement of the device shown in my Patent Number 1,890,352, issued December 6, 1932, entitled Crossing signals.

The present inventionV embodies the same general principles as those disclosed -in the aforesaid patent. A signal means adapted to control trafc across a railroad track reciprocates between a Stop position and a Go or clear position, one movement of the reciprocation being effected by power-driven mechanism, and the opposite movement being accomplished by the force of gravity. By this arrangement, the power-driven movement not only moves the signal member from one position to another, but also, by displacing a suitable weight against the force of gravity, stores energy in the form of energy of position to be used in accomplishing the second and opposite movement of the signal member. Preferably, the signal member indicates Go when it is at the end of the power-driven movement, energy then being stored for the opposite movement of the signal member to the Stop position. In other words, when the signal is in the clear position, potential energy is available for the second movement, and an approaching train or control vehicle merely releases the stored energy. After the departure of the train, the reverse power-driven movement isautomatically initiated and then 'completed to place the parts in their Go position. 'I'he word normal as hereinafter used will refer to the position ofthe mechanism at the Go or clear position of the signal.

An important advantage of this arrangement is that if the power-driven mechanism fails, the signal member will subsequently fail to move from the Stop position when the train clears the controlled zone, thereby calling attention to the condition of the mechanism before any serious accident can be caused by the break-down.

An additional safety feature is that the signal is maintained in the Go position only so long as an electric control circuit is energized. Consequently, Whenever the control 'circuit fails or is broken by accident or for some other reason, the signal member Will immediately move to the Stop position, regardless of the proximity of a train, thereby calling attention to the need for immediate repair.

As in my previous disclosure, I prefer that the power-driven mechanism comprise an hydraulic lift actuated by an electrically driven pump.

1935, Serial No. 11,597

One object of my improvement is to provide for maintaining the signal in the Go position by a. positive latch instead of by fluid pressure, and to further provide for opening the latch in a positive manner by utilizing the impact of an auxiliary weight released when the train enters the control zone. Another object of my invention is to provide for controlled non-uniform movement of the signal member from the Go position to the Stop position. The signal is arranged to move suddenly to an intermediate warning position and then to proceed slowly to the Stop position, the latter movement being subject to precise adjustment.

The above and other objects and advantages of my improvement will be apparent from the detailed description `to follow, considered with the accompanying drawings, in which- Fig. 1 is a side elevation of my invention;

Fig. 2 is an enlarged side elevation with the 20 outer housing or casing shown in section;

Fig. 3 is a vertical, medial section of Fig. 2 on a somewhat larger scale;

Fig. 4 is a plan view of the mechanism withinv the signal housing, taken with the signal in the Stop position;

Fig. 5 is similar to Fig. 4, with the signal in the Go position;

Fig. 6 is an elevation of the mechanism in the upper part of the housing, with the signal in the Stop position;

Fig. 7 is similar to Fig. 6, with the signal in the Go position;

Fig. 8 is a horizontal section of the signal mechansm, taken as indicated by the line 8 8 o-f 35 Fig. '7;

Fig. 9 is a vertical section, taken as indicated by line 9--9 of Fig. 8;

Fig. 10 is a vertical section, taken as indicated by line IIJ- l0 of Fig. 9, with the signal mecha- 4,0 nism in the Stop position;

Fig. 11 is similar to Fig. l0, with the signal mechanism at the end of theY movement to the Go position;

Fig. 12 is a vertical section as indicated by the '45 line |2-I2 of Fig. 8, with the signal in the Stop position; A'

Fig. 13 is similar to Fig. 12, showing the movable parts at the end of the movement tothe Go position; l

Fig. 14 is a wiring diagram, indicating one electrical arrangement that may be embodied in the invention; and

Fig. 15 is a wiring diagram showing a second electrical arrangement that may be employed.

' vertical signal shaft.

The mechanism of the signal is housed in a cylindrical casing having a `conical top 2l. 'Ihe base plate 22 of the casing is integral with a platform 23 that supports the major part of the mechanism.

My invention is not, limited to any particular type of signal member, nor any particular elevation of the signal member above the ground. yIt is an object of the preferred form of my invention, however, to provide a lower signal member in the form of a barrier, generally designated by numeral 2li, mounted to yield to the impact of a vehicleand an upper signal member, generally designated by numeral 25, independent of the barrier and of sufcient elevation to clear vehicles. The manner in which the requisite degree of independence of these two signal members may be attained will become apparent with further description.

The upper signal member 25 includesV a horizontally extending arm 25 rigidly mounted to vertical signal shaft 2l byv means. of a suitable T tting 28, the arm being suitably braced by a cable 26a. extending to a top tting 25 on-the The barrier, or lower signal member, 24 is mounted on a horizontal arm 30 extending from a sleeve 3l that rotatably embracesthe signal shaft. Preferably, barrier 25 is counterbalanced by a suitable weight 32on a diametrically opposite arm 33 also mounted on sleeve 3l, a suitable cable 313 bracing the barrier and two similar cables 35 and 35 bracing arm 33.

To protect the upper end of sleeve 3l from moisture, an'overhanging conical protector 3l may be suitably positioned on signal shaft 2l; and for further'protection from the weather, a coni- .cal shield 38, having a vertical skirt 35, may be connected to sleeve 3l in a position to cover the tcp of the signal casing, as shown.

Signal sleeve 3l is operatively associated with a signal drive shaft 40 through a flexible connection that will permit, under certain circumstances, a degree of independent movement. The purpose Yhere is to avoid damage to the mechanism by a vehicle colliding with barrier 24. Such a flexible connection may comprise a suitable yoke l embracing and supporting sleeve 3l, Y

together with a complementary revolvable signal base 52 suitably mounted on the upper end of drive shaft 40 as by screw-threaded engagement. Yoke 4l has two diametrically positioned arms 43 that turn downward and terminate in suitable non-friction members, such as revolvably mounted balls l5 that ride on signal base 42. Yoke ll floats on signal base 52 and is kept centered with respect to the signal base by virtue of the fact that the lower end of signal shaft 21 is embraced by the signal base. A suitable key causes signal shaft 21 to turn with signal base 52.

Signal base 42 has a radial flange 46, at the periphery of which a vertically disposed annular flange l'l serves as a circular trackfor balls'llt of yoke 4i. At diametrically opposite points, annular flange 4l rises to apexes 58 and at 90 degrees from the apexes the annular ange falls todiametrically opposite low points or valleys @5. It is apparent that normally yoke 4l will ride in valleys 49, barrier 24 turning in-vertical alignment with upper signal member 25, and that should a vehicle collide with barrier 265, displacing it from its usual alignment with member 25, a vcam action will be provided to return the barrier to such alignment.V f

The vlower end of signal drive shaft is revolvably supported by a suitable thrust bearing 5l) mounted in top casting 5l of the main hydraulic cylinder 52. The upper end of the signal drive shaft is kept in vertical alignment by a suitable annular bearing 53 embracing the lower portion of signal base 42. This upper bearing is mounted on a horizontal plate 54 that is supported largely by casing 25. Either or both of these bearings may support the major portion of drive shaft 45 and the associated elements heretofore described.

Drive shaft lll is actuated by movement of a suitable weight 55, the operative connection between the two being such that vertical movement of weight 55 from the position shown in Fig. 6 to that shown in Fig. 'l causes shaft 45 to rotate approximately 90 degrees in one direction, and the reverse movement of weight 55 causes the reverse rotation of the shaft. Preferably, this operative connection is provided by means of spiral ribs 56 associated with. weight 55 in mesh with complementary spiral grooves 5l on the periphery of drive shaft 55. The ribs may be formed in a hard Babbitt liner 58 of a nickeled steel sleeve 59 incorporated in weight 55. Weight 55 may be held against axial rotation by suitable guide rods E55 that are slidably embraced by bronze bushings 6l incorporated in the body of the weight.

The mass ofweight 55 is such that byforce of gravity alone it will move freely, if unsupported, from its normal position at the upper end of its range of movement-to its lowermost position, thereby revolving shaft 45 to place the two signal members in the Stop position.

The power means for moving weight 55 upward preferably includes a hydraulic lift. In the construction-shown, hydraulic cylinder 52, mounted on platform 23, encloses a suitable piston 62 from Vwhich two spaced piston rods 53 extend upward, terminating in weight 55.

To limit the upward movement of the piston under hydraulic action, it may be provided with a suitable relief valve 54 that normally covers relief passages 55. The valve includes a stem 56 extending upward a suitable distance towards top casting 5l. The valve is normally maintained in a closed position by virtue of a suitable helical spring 6l confined between piston 62 and a stop 68 on the stem.

It may be noted here that in the construction shown the piston reciprocates only over the lower portion of cylinder 52. The pump, generally designated by numeral 59, is mounted below the cylinder in the space between platform 23 and base plate 22. Thel pump may be of the gear'type, comprising two interlocking rotary elements 10 and ll in pump chamber l2. The two rotary elements are mounted, respectively, onshafts 13 and lll, shaft it being driven by a suitable motor Any fluid may be used in the hydraulic lift, preferably a suitable grade of oil. The space in cylinder 52 above the piston is utilized as a reservoir, the oil being pumped out of the reservoir into the cylinder under the piston to raise the weight, and the oil being returned to the reservoir when the weight is permitted to force the piston downward. The drawings show an arrangement that may be employed to provide such a cycle of fluid movements. Y

From a port 'i6 in the cylinder wall just above the upper position of piston 62 (Figs. 12 and 13),

a down-flow passage 'll (Fig. 10) leads to pump.

chamber l2. From the outlet side of the pump a pressure passage 85 leads to the bottom of a verestY tically disposed valve chamber 8|, in which a valve 82 is free to move longitudinally from a normal lower position, shown in Fig. 10, to an alternate higher position, shown in Fig. 11, the valve moving upward by huid pressure from the pump. The Valve includes an extensive stem 83 terminating in a valve head 84. Preferably, the gravitational return of the valve is facilitated by a helical spring 85 conned between valve head 84 and the upper end wall 88 of the valve chamber. End wall 86 has a suitable bleeder port 81 to provide ready escape of any fluid trapped above the valve head.

When the valve is in its uppermost position, it clears a lower valve port 88 from which a passage 89 leads to a port 98 in the cylinder wall below the lowermost position of piston 62. In such position of the valve an upper valve port 9| is cut off from both pump pressure passage 88 and the lower cylinder passage 89. In the lowermost position of the valve (Fig. 10), pressure passage 80 is cut off and communication is established between the space in the cylinder under piston 62 and the space in the cylinder above piston'62 as follows: port 98, lower cylinder passage 89, port 88, valve chamber 8|, upper valve port 9|, up-flow passage 92, and spaced ports 93 and 94 in the cylinder wall above the uppermost position of the piston.

It will be noted that the arrangement is equiv-- alent to an ordinary three-way valve responsive to fluid pressure, i. e., when the pump is in operation fluid pressure forces the valve to its uppermost position, thereby placing the pump in communication with the cylinder under the piston, and, when the pump ceases operation, thevalve automatically returns to a position placing the lowermost portion of the cylinder in communication with the uppermost portion of the cylinder.

Since oil trapped in pump .pressurel passage 88 may hinderif not prevent, the downward return of valve member 82, either the pump must permit sufficient reverse leakage to release the trapped oil or a suitably Ydimensioned bleeder passage 95 must be provided between pressure passage 88 and down-flow passage 11.

Normally, the weight is held at its uppermost position independent of the hydraulic lift by virtue of a lock means that will be described later. When a train or control vehicle enters the control zone of the trackthe weight is released to gravitate downward, thereby turning the signal to the stop position and forcing oil from the bottom of the cylinder to the top of the cylinder through passage 92. One of the objects of this invention is to provide relatively fast movement of the signal for the first degrees and relatively slow movement for the remaining degrees. This object may be accomplished by controlling the flow 'of iiuid through passage 92 in accordance with the desired rate of movement of the signal.

For this purpose, the upper portion of passage 92 is enlarged to a time-control cylinder 96 in which reciprocates a time-control plunger 91. By

means of a connecting rod 98 extending upward through a suitable packing gland 99, time-control plunger 91 is connected to a bracket |88 integral with weight 55 (Fig. '1). Plunger 91 has one or more longitudinal passages |0| dimensioned to suitably restrain the iiow of oil through up-iiow passage 92.' Preferably, adjustment of degree of restraint of oil flow is provided by a suitably apertured complementary disk |02 having apertures corresponding to passages |8| in the time-control lplunger. 'I'his disk may be held xed by nut |83 at any of various positions partially closing passages |8|.

The reasons for providing two ports 93 and 94 spaced as shown will now be apparent. normal position of the signal, time-control plunger 91 clears lowermost port 93 by a distance corresponding to the rst 30 degrees of the signal movement. When the weight is released to gravitate downward, the time-control plunger will not restrict the ow of uid through passage 92 until it begins to cut 01T ports 93. Thereafter, however, the downward movement of the weight will be retarded by the restricted flow of the oil through apertures |8| until the time-control piston reaches its lowermost position, indicated in Fig. 10. Two spaced ports are'required so that when the time-control plunger is passing over lowermost port 93, uppermost port 94 is available for'oil passage.

The latch means to releasably retain the weight at its normal uppermost position independent of the hydraulic lift may be associated either with the weight itself or with drive shaft 48. In the arrangement shown, the latch is associated with the shaft through signal base 42.

A suitable latch pinion 84 (Figs. 4 7) mounted on the periphery of signal base 42 in radial alignment to the axis of shaft 48, meshes with an arcuate rack mounted on plate 54. A pawl |86 overhanging the normal position of pinion |84 is pivotally mounted in a suitable latch bracket |81, the bracket being mounted on plate 54.

Mounted in bracket |81 on the same axis as pawl |06 is a latch rocker arm |88. The inner end of this rocker arm is provided with an arcuate slot |89 which coniines a pin ||8 extending laterally from pawl |86. This inner end of the rocker arm is operatively connected by a downwardly extending portion |88a to a suitable motor cut-ofi" switch mounted on plate 54, which switch may be of the mercury type adapted to rock between open and closed positions. When the inner end of the rocker arm is down, i. e., in the normal position shown in Fig. 7, switch is open; and when the rocker arm is in the alternate L position of 'Fig 6, the motor cut-off switch is closed. It will be noted that when the inner end of the rocker arm is down, slot |89 permits pivotal movement of the latch in a range of engagement with pinion |84, but when the inner end of the rocker arm is at its uppermost position (Fig. 6) the pawl is lifted clear of the pinion.

`From the outer forked end of rocker arm |88 pivotally depends` a stirrup l2 that passes through a vertical slot I3 in a latch weight |4. An armf aturc` SI5, integral M, is designed to electro-magnet H8.

with the upper end of weight co-operate with -a U-shaped Y Electro-magnet 6 has a suitable coil H8@ and is mounted on a horizontal extension ||8 ofv bracket |81, the electromagnet being within the fork of rocker arm |88.

In the normal position of the various parts of the lat-ch mechanism shown in Fig. '7, the latch weight is held at its uppermost position by virtue of electro-magnetic coupling between armature H5 and electro-magnet H8, and rocker arm |88 is held in a position with the inner end depressed by virtue of the fact that stirrup ||2 is held up by the bottom of slot H3.

When the electro-magnet ||6 is de-energized by a train entering the control zone of the track, latch weight 4 is released to gravitate downward. Slot ||3 is of suiiicient length to provide al substantial degree of lost motion between latch weight ||4 and stirrup U2, so that the re- In the strength to hold the weight suspended in the Y position shown in Fig. '1, it is not of sufficient strength to draw the weight upward against gravity from the position shown in Fig. 6. I have,

therefore, provided automatic means for restoring the latch weight to its normal position upon the arrival of signal weight 55 position.

vBelow the weight, a vertically disposed cutoff cylinder ||9 communicates with main cylinder 52 by an upper passage |29 and a lower passage |2|, lower passage |2| opening thence to a chamber |22 on the wall of the m-ain cylinder 52. Towards the upper end ofrchamber |22 a bore or group of bores generally designated by numeral |23 extends through the wall of cylinder 52, and a similar bore or group of bores, generally designated by numeral |24, extends through the wall of the main cylinder near the lower end of chamber |22. A suitable cut-off plunger |25 slidably mounted in cut-off cylinder ||9 is mounted on a rod` |26. The rod extends Vupward through a packing gland |21 into a vertical bore |28 in weight ||4. A suitable helical spring |29 .embraces rod |26 below'weight ||4, the spring resting upon a suitable sleeve |30 adjustably mounted on the rod. Y r Normally, i. e., when the signal is in the clear" position and notrain is in the control zone of the track, rod |26 rests upon the bottom end plate |3I, holding cut-off plunger |25 at a position just above passage l2 and no eiective pressure is exerted by spring |29 against the bottom of latch weight |l4. The normal positions of these elements are shown in Figs. 7 and 12.

When latch weight ||4 is released by a train entering the control zone, it m-ay fall far enough to partially contract spring |29, as shown in Fig. 6. As soon as the train clears the control zone, motor 15 is energized and pump 69 begins to deliver oil to the bottom of cylinder 52 beneath piston 62. When piston 62, on its upward movement, opens the lowermost of bores |24, oil under pressure escapes into chamber |22 and passage |2| to exert pressure on the under side of cut-ofi plunger |25. The full force of the oil pump is not delivered against the cut-off plunger initial- 1y, so spaced that momentarily oil ows both outward from underneath the piston through one or more bores |24 and inward above the piston through one or more bores |23. This momentary condition yceases as piston 62 moves upward to completely cover bores |23 and completely uncover all of bores |24, so that'the full force of the pump is thereafter delivered against cut-off plunger |25.

The cut-oir` plunger is forced upward, carrying with it rod |26, the upward movement forcing weight ||4 into the normal position shown in Fig. '1. It will be noted that spring |29 serves as a shock-absorberL and permits a certain latitude in the adjustment of sleeve |36. If, for any reason, motor cut-off switch is not closed by the arrangement described to stop lthe pump, damage to the mechanism will be prevented by at its uppermost however, because bores |23 and bores |24 areY Vis contemplated that all pressure in cylinder 52 beneath the piston will Lbe released immediately after the pump stops by virtue of valve 82 returning to its lowermost position and thereby providing -free communication from port 96'at the bottom of the cylinder to ports V93 and 94 at the top of the cylinder.,

In my previously granted patent, referred to above, I disclose a'wiring diagram, the principles of which may be adapted to the' present device. The essence ofv such an arrangement consists in providing-two control switches, bothof which must be closed to energize the signal motor,one

being -a mechanically operated switch that opens only when the signal is -in thev Go position, the other being an electrically operated switch open only when a` train'is in the control zone.v Both switches, in such an arrangement, will be closed to operate the motor whenever the signal is in the Stop position and no train is in the control zone. l 5 l A simple form of such a wiring diagram is shown in Fig. 14. .Relay |32 is normally energized in the closed position by wires |33 and |34 that are part of a circuit associated with the control zone of the railroad track. Whenever a train entersthe control zone this circuit is shortcircuited to de-energize relay |32, thereby breaking the normal circuit through electromagnet ||6. This last named'normal circuit includes wire |35, battery |36, wire |31, relay-member |33, and wire |39 to the other side of the electromagnet. Y When the electro-magnet releases .weight |49 of the Vwiring diagram, which represents latch weight' ||4 in the -device itself, a switch member 543e connects contacts |4| and |42, Vthe switch member and two contacts representing cut-off switchl As long as thetrain is in the control zone, relay |38'remains open and switch member 140@ bridges contacts |,4I and |42. As soon as the train leaves the control zone, the signal being in the Stop position, relay |32 closes to re-establish the normal vcircuit through electro-magnet l i6 and also the following circuit through motor 15: battery., |36, wire |35, wire |43, motor 15, wirev |44, switch memberrllllla, wire |45, wire|39, relay member |38 and wire |31 back to battery |36.

The wiring diagram of Fig. 15 is similar to Fig. 14, but provides for controlling the motor through a motor relay |46. Corresponding parts of the two wiring diagrams are given corresponding numbers. Normally, electro-magnet ||6 is energized by the circuit above described and sinceV switch member |46a is spaced from contacts |4| and |42, relay 46 is de-energized.

When a train enters the control, zone, relay 32 opens, thereby de-energizing electro-magnet |6. When switch member |4611 drops to bridge contacts |4| and |742, relay |46 does not close because the relay circuit includes relay member |38. When, however, the train leaves the control zone and relayr|32 closes, motor relay |46`is energized through the following circuit: battery |36, wire |31, relay member |38, wire |39, wire |45, switch member |49a, wire |41, coil of relay |46, wire |48, and wire back to battery |36. When relay |46 is thereby energized, the follownal will remain in the Stop ing motor circuit is established: battery |36, wire |31, wire |49, relay member |50, wire |5|, motor 15, wireV |43 and wire 4|35 back to battery |36.

The operation of vmy invention may be readily understood from vthe foregoing description. When the various moving parts are in their normal positions with'the-control zone ofthe track clear,`track relay |32-is closed; electro-magnet H6 is energized; cut-ofi switch |||is open; the signal is in the Go position; weight 55 and piston 62 are at their uppermost positions by virtue of the latch mechanism; latch weight H4 is held-at its highest position by electro-magnet H6; cut-off plunger |25 rests at its lowermost position; and since rthe motor and pump are idle, valve 82 is 'at its lowermost position, providing free communication between the portion of the cylinder below the piston and the portion ofthe cylinder above the piston.

As soon as a train enters the control zone, thereby de-energizing the' track relay, electromagnet I6 is de-energized, releasing latch weight H4. The latch weight drops with considerable impact against stirrup H2, thereby disengaging the latch with'a jerk, and at the same time closing motor cut-otfswitch' 'I l I. The latch is held suspended `in the position shown in Fig. 6. Pinion |04, being free to rotate, moves around rack |05 as signal base 42 and shaft 40 are rotatedpby the downward movement of weight 55. V'I'he signal swings rapidly 30 degrees until time-control plunger 91 becomes effective, and then proceeds more slowly the remaining 60 degrees to .the Stop position. Y

As soon as the control vzone of the track is again clear, the motor circuit is re-established, as heretofore described, and pump 69 begins to deliver oil through the cylinder under piston 62, valve 82' being moved to its upper position automatically. The pump continues to force piston 62 and weight 55 upward until oil escaping from the cylinder through bores |24 forces cut-oli plunger upward to close cut-oir fswitch and to permit pawl |06 to drop into engagement with pinion |04.

If the track circuit fails for any reason, relay |32 will open, thereby de-energizing electro-magnet H5 to cause the signal to turn to the Stop position. If the motor circuit should fail, the track circuit remaining operative, the signal will remain in the Go position uniti] a train in the control zone causes the weight to be released to turn the signal to the Stop position; and then upon re-energization of the track relay, the sigposition, thereby inviting attention to the motor circuit. It is apparent that by providing gravitational movement of the signal from the Go to the Stop position, I have avoided many Vof the hazards ordinarily inherent in'an electrically operated signal.

I have described a preferred form of my ine vention in specific detail for the purpose of disclosing and illustrating the principles involved. Since this preferred form suggests a wide range of modiications that come within the spirit of my invention, I reserve the right to all such modications that are properly within the purview'of my appended claims.

Having described my invention, I claim:

1'. In a signal mechanism adapted to gravitate from one signal position to another, the combination of: a latch to releasably hold the signal mechanism against gravitation; a latch weight;

an electro-magnet adapted to hold the latch weight elevated, said weight being adapted to open the latch by impact when released by the electro-magnet; and an electric circuit normally energizing said electro-magnet, said circuit being adapted to be interrupted by'an approaching` control vehicle to release the latch weight.

2. A signal having, in combination: a signal member movable between two positions; a signal weight movable from a lower position to an upper position and vice versa, said signal weight being operatively connected to the signal memser whereby the upward movement of the signal weight will move the signal to one position and the reverse gravitation of the signal weight will move the signal to the alternate position; a latch to releasably hold the signal weight against gravitation; a latch weight; an electro-magnet adapted to hold the latch weight elevated, said weight beingY adapted to open the latch by impact when released by the electro-magnet; an electric circuit normally energizing said electro-magnet, said circuit being adapted to be interrupted by an approaching control vehicle to release the latch weight; and power means adapted to be energized upon departure of the control vehicle to lift the signal weight to its normal latched position and to lift the latch weight to the electro-magnet.

3. A signal having, in combination: a signal member movable between two positions; a signal weight movable from a lower position to an upper position and vice versa, said signal weight being cneerativclyY connected to the signal member whereby the upward movement of the signal weight will move the signal to one positionV and the reverse gravitation of the signal weight will move' the signal to the alternate position; a latch to releasably hold the signal weight against gravitation; a latch weight; an electro-magnet adapted to hold the weight being adapted to open the latch by impact when released by the electro-magnet; an electric circuitV normally energizing said electro-magnet, said circuit being adapted to be interrupted by an approaching controlv vehicle to release the latch weight; electrically actuated means to lift the signal weight and the latch weight back to their elevated positions; a second electric circuit to energize said electrically actuated means; and two switches controlling said second circuit, the circuit being energized only when both switches are closed, one of said switches being normally closed and being adapted to open temporarily in response to the approaching control vehicle, the other switch being adapted to open automatically Vwhen the signal weight reaches its normal latched position and to close when the signal weight drops from said normal position.

4. A signal having, in combination: a signal member movable from a Go to a St0p posi tion and vice versa; a signal weight movable from a lower position to an upper position and vice versa, said signal weight being operatively connected to the signal member whereby the upward movement of the weight will move the signal member to the Go position and the reverse gravitation of the signal weight will move the signal member to the Stop position; means to lift the signal weight against gravity; means to retain the signal weightat its higher position, said retaining means being adapted to release the signal weight in response to the approach of a control vehicle; a fluid chamber having an outlet passage; means operated by the falling weight latch weight elevated, said to expel fluid from the chamber through said outlet passage; and a time control means adapted to be moved by the falling weight against the iuid stream in said outlet passage, said control means restricting flow through Ysaid passage, thereby retarding the fall of the plunger. Y

5. A'signal having, in combination: a signal member movable in one direction from a Go position to an intermediate warning position and then to a Stop position and in the opposite direction from the Stop position back to the Go position; a signal weight movable from a lower position to an upper position and vice versa, said signal weight being operatively connected to the signal member whereby the upward movement of the weight will move the signal member to the Go position and the reverse gravitation of the weight will move the signal member rst to the warning position and then to the Stop position; means to lift the signal weight against gravity; means to retain the signal weight at its higher position, said retaining means being adapted to release the weight in response to the approach of a control vehicle; and means to retard the fall of the weight between the warning position and the Stop position.

6. A signal having, in combination: a signal member movable in one direction from a Go position to an intermediate warning position and then to a Stop position, and in the opposite direction from the Stop position back to the Go position; a signal weight movable from a lower position to an upper position and vice versa, said signal weight being operatively connected to the signal member whereby the upward movement of the weight will move theV signal member to the Go position, and the reverse gravitation of the weight will move the signal member to the warning position and then to the Stop position; means to lift the signal weight against gravity; means to retain the signal weight at its higher position, said retaining means being adapted to release the weight in response to the approach of a control vehicle; a fluid chamber having an outlet passage; means operated by the falling weight to expel iiuid from the chamber through said outlet passage; and means operatedV by the falling weight to restrict ow through the outlet passage, said means being adapted to restrict the ow beginning at the warning position, whereby the signal will move relatively rapidly from the Go position to the warning position and thereafter move relatively slowly to the Stop position.

'LA signal having, in combination: a signal member movable between two positions; a signal weight movable from a lower position to an upper position and vice versa, said signal weight being operatively connected to the signal member whereby the upward movement of the signal weight will move the signal to one position and the reverse gravitation of the signal weight will move the signal to the alternate position; a latch means to releasably hold the signal weight at the raised position, said latch means being adapted to release the signal weight in response to the approach of a control vehicle; an hy,

draulic lift for elevating the signal weight; power means to pump uid into said hydraulic lift, thereby elevating the signal weight to the latched position, said hydraulic lift having an outlet passage for the release of said iiuid under pressure from the falling weight; and an apertured plunger movable by the falling weight into said outlet passageagainst the uid stream to retard the fall of the weight.

8. A signal having, in combination: a signal member movable between two positions; a signal weight movable from a lower position to an upper position, and vice versa, said signal weight being operatively connected to the signal member whereby the upward movement of the signal weight will move the signal to one position and the reverse gravitation of the signal weight will move the signal to the alternate position; a latch means to releasably hold the signal weight at the raised position, said latch means beingV adapted to release the signal weight in response to the approach of a control vehicle; an hydraulic cylinder; a piston in said cylinder operatively connected with the signal weight; a power driven pump to deliver fluid to the cylinder under the piston, thereby elevating the weight; and control means to stop the pump when the weight reaches its elevated position, said control means including an auxiliary hydraulic means having its inlet connected to the cylinder adjacent the desiredY vmechanism adapted to gravitate from a iirst signal position to a second signal position; a latch to releasably hold said mechanism atthe rst position; a latch weight; an electro-magnet adapted to hold the latch weight elevated, said weight being adapted to open the latch by impact when released by the electro-magnet; an electric circuit normally energizing said electromagnet, said. circuit beingadapted to be Ainterrupted by an aproaching control vehicle to release the latch weight; power driven hydraulic means to move the signal mechanism against gravity from the second signal position to the first signal position for engagement with said latch; and auxiliary hydraulic meansadaptedto receive uid under Apressure from the lfirst hydraulic means for the purpose of restoring the latch weight to magnetic engagement with the electro-magnet at the latchedposition of the. mechanism.

l0. A signal having, in combination: a signal mechanism adapted to gravitateV from a first signal position to a second signal position; a latch to releasably hold said mechanism at the first position; a latch weight; an electro-magnet adapted to hold the latch weight elevated, saidY weight being adapted to open the latch by impact when releasedV by the electro-magnet; an electric circuit normally energizing said electro-magnet,

cuit arranged to cause the circuit to be energizedwhen both switches are closed, theiirst of said switches being normally closed and being adapted to opentemporarily'in response to the approaching vcontrol vehicle, the second switch havingv` an inherent tendency to close; means associated with V.

said, second Vswitch and the electro-magnet whereby theelectro-magnet when energized holds said second switch open; and auxiliary hydraulic means adapted to receive uid under pressure from the first hydraulic means for the purpose of restoring the latch weight to magnetic engagement with the electro-magnet at the latched position of the mechanism, and for the further purpose of opening said second switch when the signal mechanism reaches the latched position.

11. A signal having, in combination: a signal mechanism adapted to gravitate from a first signal position to a second signal position; a latch to releasably hold said mechanism at the rst position; a latch weight; an electro-magnet adapted to hold the latch weight elevated, said weight being adapted to open the latch by impact when released by the electro-magnet; an electric circuit normally energizing said electro-magnet, said circuit being adapted to be interrupted by an approaching control vehicle to release the latch weight; Yelectrically driven hydraulic means to move the signal mechanism against gravity from the second signal position to the rst signal position for engagement with said latch; an electric circuit to energize said hydraulic means; two electric switches associated with the second circuit arranged to cause the circuit to be energized when both switches are closed, the rst of said switches being normally closed and being adapted to open temporarily in response to the approaching control vehicle, the second switch havin-g an inherent tendency to close; Vmeans to hold said second switch open while the signal mechanism is in the rst'position; auxiliary hydraulic means adapted to receive iluid under pressure from the first hydraulic means for the purpose of restoring the latch weight to magnetic engagement with the electro-magnet at the latched position of the mechanism; and means restricting flow of fluid from the first hydraulic means under pressure from the gravitating mechanism, thereby controlling movement of the mechanism from the iirst signal position to the second signal position.

12. A signal having, in combination: a signal member mounted to rotate between two positions; a signal weight movable from a lower position to an upper position, and vice versa, said signal weight being operatively connected to the signal member whereby non-rotary upward movement of the signal weight will rotate the signal to one position and reverse non-rotary gravitation of the signal weight will move the signal to the alternate position; guidemeans to prevent rotation of the weight; an electrical latch means adapted when energized to releasably hold vtheA signal' weight at the raised position; an electric circuit normally energizing the latch means, said circuit being adapted to be interrupted by an approaching control vehicle, thereby de-energizing the latch to release the signal weight; and I power means adapted to Abe energized upon the departure of ther control vehicleto lift the signal weight back to its normal latched position,

13. Ina signal of the class described, a yielding connection between a vertical shaft and a horizontally pivoted signal member, said connection Y comprising: a base mounted on the vertical shaft,

said base presenting on its upper surface a pluthe vertices of said valleys at all positions of Vthe signal member.

MERCER D. WILSON. 

